Project Summary/Abstract Sleep problems among youth are highly prevalent and associated with a broad range of emotional, behavioral, cognitive, and physical issues. Indeed, sleep problems are ubiquitous to mental health disorders and evidence supports sleep problems as a precursor to internalizing pathology in youth. The early adolescence developmental period (i.e., peri-puberty) presents as a particularly vulnerable stage for the negative effects of insufficient and/or poor-quality sleep. When considering influences on youth?s sleep, parenting behaviors and the parent-youth relationship have been demonstrated to predict the development and maintenance of poor sleep in youth. However, research is lacking on the specificity of which dimensions of parenting behaviors (e.g., nighttime parenting, general parenting practices) are most strongly associated with youth sleep problems. Further, parenting practices have scarcely been addressed in sleep interventions for adolescents, especially in the context of preventing mental health difficulties (e.g., anxiety, depression) that typically accompany sleep problems and that are occurring at escalating rates in adolescents. Considering the negative sequelae associated with experiencing sleep problems in early adolescence, the current proposal aims to advance the understanding of the influence of specific parenting practices on disrupted sleep in youth by leveraging the sponsors? clinical trial to examine intervention outcomes of a family-focused sleep group intervention for peri- pubertal youth with co-occurring sleep and internalizing problems when compared to a treatment-as-usual youth- focused sleep intervention. The proposed study will employ a comprehensive, objective, multi-method, and multi- informant examination of trajectories in daytime and nighttime parenting practices and of youth sleep health using methodology such as ecological momentary assessment and actigraphy (Research Aim 1). Further, group differences in the trajectory of change in parenting practices and youth sleep (Research Aim 2) will also be examined. Lastly, the proposed study aims to examine the mechanisms underlying improvements in youth sleep and psychosocial health (Research Aim 3). Dr. McMakin will provide mentorship on the assessment and treatment of sleep problems and psychosocial well-being in peri-pubertal youth (Training Goal #1). Dr. Parent and Dr. Forehand will consult on the impact of parenting practices on youth sleep health and psychosocial development (Training Goal #2). Dr. Timmons and Dr. Hayes will consult on developing advanced quantitative skills to examine intensive, high volume streams of data on parenting practices and youth sleep (Training Goal #3). Drs. McMakin and Parent will supervise and consult on the overall proposed study and ethics. Findings will advance the understanding of transactional models between youth sleep problems and parenting and inform prevention and intervention services for youth with co-occurring sleep and behavioral and emotional difficulties. The proposed research aims and training goals have been intentionally delineated to prepare the applicant for a career as an independent investigator focused on studying youth sleep health within the family context.